The blue-line/red-line diverging price graph is such a great litmus test for someone's ability to do even a single round of interrogation.

Here's the question to ask:

Which of these have economies of scale, are scale-neutral, or have diseconomies of scale?

Ta-da!

Three sectors that have diseconomies of scale: education, healthcare, housing.

Essential services aggregate in the red because non-essential services that have diseconomies of scale... wait for it... never achieve scale! Then you have government step in because the services are important (often with hard-to-capture upside, ergo limited incentive for private investment to begin with), and now you have an aggregation of essential, expensive, government-involved services.